1. Field of the Invention
The present invention relates to a method of adjusting a size of a packet transmitted from a wireless communications system. More particularly, the present invention relates to a method and an apparatus for dynamically managing a packet segment threshold that are capable of reducing the frequency of packet transmission errors by monitoring a state, i.e., a condition, of a wireless channel and dynamically varying the packet segment threshold depending on the wireless channel state.
2. Description of the Related Art
In a wired communications system, communication channels are relatively stable in terms of operation. Accordingly, segment threshold, transmission power, retransmission technique variables, and forward error correction (FEC) levels, which are used as system parameters, generally have fixed values. However, in terms of channel environment, wireless communications are quite different from wired communications. Therefore, if protocols that are used in wired communications are directly applied to wireless communications, a significant amount of packet loss may occur depending on a state, i.e., a condition, of a channel. Accordingly, wireless communications require new protocols capable of flexibly and adaptively responding to characteristics and a state of a communications channel that may vary considerably from moment-to-moment.
In a conventional wireless communications system, each access point (AP) determines a fixed packet segment threshold used by wireless terminals, with consideration of a corresponding frequency band and service area thereof. Segment threshold, which represents the maximum packet size when transmitting data on a packet-by-packet basis, directly affects transmission throughput, i.e., the amount of data transmitted from one place to another at any given period of time.
If the segment threshold for transmitting a packet is set high, packet overhead decreases. In this case, a better channel environment results in higher throughput, and a poorer channel environment results in greater data loss. Greater data loss indicates more frequent retransmission requests. Alternately, if the segment threshold is set low, packet overhead increases. In this case, a superior channel environment results in lower throughput, and a poorer channel environment decreases the likelihood of data loss. Therefore, in order to increase throughput and reduce data loss in a wireless communications system, segment threshold needs to vary depending on a current state of a wireless communications channel.